Integrate FastMCP

This commit integrates FastMCP, a high-level MCP server implementation originally written by Jeremiah Lowin,
into the official MCP SDK. It also updates dependencies and adds new dev dependencies.
It moves the existing SDK into a .lowlevel .

src/mcp/server/fastmcp/tools/tool_manager.py

@@ -0,0 +1,54 @@
+from mcp.server.fastmcp.exceptions import ToolError
+from mcp.server.fastmcp.tools.base import Tool
+
+from typing import Any, Callable, TYPE_CHECKING
+from collections.abc import Callable
+
+from mcp.server.fastmcp.utilities.logging import get_logger
+
+if TYPE_CHECKING:
+    from mcp.server.fastmcp.server import Context
+
+logger = get_logger(__name__)
+
+
+class ToolManager:
+    """Manages FastMCP tools."""
+
+    def __init__(self, warn_on_duplicate_tools: bool = True):
+        self._tools: dict[str, Tool] = {}
+        self.warn_on_duplicate_tools = warn_on_duplicate_tools
+
+    def get_tool(self, name: str) -> Tool | None:
+        """Get tool by name."""
+        return self._tools.get(name)
+
+    def list_tools(self) -> list[Tool]:
+        """List all registered tools."""
+        return list(self._tools.values())
+
+    def add_tool(
+        self,
+        fn: Callable,
+        name: str | None = None,
+        description: str | None = None,
+    ) -> Tool:
+        """Add a tool to the server."""
+        tool = Tool.from_function(fn, name=name, description=description)
+        existing = self._tools.get(tool.name)
+        if existing:
+            if self.warn_on_duplicate_tools:
+                logger.warning(f"Tool already exists: {tool.name}")
+            return existing
+        self._tools[tool.name] = tool
+        return tool
+
+    async def call_tool(
+        self, name: str, arguments: dict, context: "Context | None" = None
+    ) -> Any:
+        """Call a tool by name with arguments."""
+        tool = self.get_tool(name)
+        if not tool:
+            raise ToolError(f"Unknown tool: {name}")
+
+        return await tool.run(arguments, context=context)